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<div class="refentry">
<a name="boostbook.dtd.function"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2><span class="refentrytitle">
          BoostBook element <code class="sgmltag-element">function</code></span></h2>
<p>function — Declares a function</p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv">function ::= 
  (<a class="link" href="template.html" title="BoostBook element template">template</a>?, <a class="link" href="type.html" title="BoostBook element type">type</a>, <a class="link" href="parameter.html" title="BoostBook element parameter">parameter</a>*, <a class="link" href="purpose.html" title="BoostBook element purpose">purpose</a>?, <a class="link" href="description.html" title="BoostBook element description">description</a>?, <a class="link" href="requires.html" title="BoostBook element requires">requires</a>?, <a class="link" href="effects.html" title="BoostBook element effects">effects</a>?, <a class="link" href="postconditions.html" title="BoostBook element postconditions">postconditions</a>?, <a class="link" href="returns.html" title="BoostBook element returns">returns</a>?, <a class="link" href="throws.html" title="BoostBook element throws">throws</a>?, <a class="link" href="complexity.html" title="BoostBook element complexity">complexity</a>?, <a class="link" href="notes.html" title="BoostBook element notes">notes</a>?, <a class="link" href="rationale.html" title="BoostBook element rationale">rationale</a>?)
</div>
<div class="refsection">
<a name="id-1.4.3.7.19.4"></a><h2>Description</h2>
<p>BoostBook functions are documented by specifying the
  function's interface (e.g., its C++ signature) and its
  behavior. Constructors, destructors, member functions, and free
  functions all use the same documentation method, although the
  top-level tags differ.</p>
<p>The behavior of functions in BoostBook is documenting using a
  style similar to that of the C++ standard, with clauses describing
  the requirements, effects, postconditions, exception behavior, and
  return values of functions.</p>
<p>The following example illustrates some constructors and a
  destructor for <code class="computeroutput"><a class="link" href="../../boost/any.html" title="Class any">boost::any</a></code>. Note that one of
  the constructors takes a single parameter whose name is "other" and
  whose type, <code class="computeroutput">const any&amp;</code> is contained in the
  &lt;paramtype&gt; element; any number of parameters may be specified
  in this way.</p>
<pre class="programlisting">&lt;class name="any"&gt;
  &lt;constructor&gt;
    &lt;postconditions&gt;&lt;para&gt;&lt;this-&gt;empty()&gt;&lt;/para&gt;&lt;/postconditions&gt;
  &lt;/constructor&gt;

  &lt;constructor&gt;
    &lt;parameter name="other"&gt;
      &lt;paramtype&gt;const &lt;classname&gt;any&lt;/classname&gt;&amp;amp;&lt;/paramtype&gt;
    &lt;/parameter&gt;

    &lt;effects&gt;
      &lt;simpara&gt; Copy constructor that copies
        content of &lt;code&gt;other&lt;/code&gt; into the new instance,
        so that any content is equivalent in both type and value to the
        content of &lt;code&gt;other&lt;/code&gt;, or empty if
        &lt;code&gt;other&lt;/code&gt; is
        empty.
      &lt;/simpara&gt;
    &lt;/effects&gt;

    &lt;throws&gt;
      &lt;simpara&gt;May fail with a
        &lt;classname&gt;std::bad_alloc&lt;/classname&gt; exception or any
        exceptions arising from the copy constructor of the
        contained type.
      &lt;/simpara&gt;
    &lt;/throws&gt;
  &lt;/constructor&gt;

  &lt;destructor&gt;
     &lt;effects&gt;&lt;simpara&gt;Releases any and all resources used in
     management of instance.&lt;/simpara&gt;&lt;/effects&gt;

     &lt;throws&gt;&lt;simpara&gt;Nothing.&lt;/simpara&gt;&lt;/throws&gt;
  &lt;/destructor&gt;
&lt;/class&gt;</pre>
</div>
<div class="refsection">
<a name="id-1.4.3.7.19.5"></a><h2>Attributes</h2>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
<col>
<col>
</colgroup>
<thead><tr>
<th>Name</th>
<th>Type</th>
<th>Value</th>
<th>Purpose</th>
</tr></thead>
<tbody>
<tr>
<td>last-revision</td>
<td>#IMPLIED</td>
<td>CDATA</td>
<td>Set to $Date$ to keep "last revised" information in sync with CVS changes</td>
</tr>
<tr>
<td>specifiers</td>
<td>#IMPLIED</td>
<td>CDATA</td>
<td>The specifiers for this function, e.g., inline, static, etc.</td>
</tr>
<tr>
<td>name</td>
<td>#REQUIRED</td>
<td>CDATA</td>
<td>The name of the element being declared to referenced</td>
</tr>
<tr>
<td>id</td>
<td>#IMPLIED</td>
<td>CDATA</td>
<td>A global identifier for this element</td>
</tr>
<tr>
<td>xml:base</td>
<td>#IMPLIED</td>
<td>CDATA</td>
<td>Implementation detail used by XIncludes</td>
</tr>
</tbody>
</table></div>
</div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 2003-2005 Douglas Gregor<p>Distributed under the Boost Software License, Version 1.0.
      (See accompanying file LICENSE_1_0.txt or copy at
      <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>).
      </p>
</div></td>
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